1. Field of the Invention
The present invention relates to a composition for detecting or quantitatively measuring a peroxide active material in a sample. More particularly, the present invention relates to a composition for detecting or quantitatively measuring a peroxide active material which can eliminate an influence of a reducing compound such as ascorbic acid and the like contained in the sample.
2. Description of the Prior Art
When a peroxide active material in a sample is detected or quantitatively measured, ascorbic acid contained in the sample will have several adverse affects on the measurement of the peroxide active material, since it acts as a strong reducing agent. To avoid the influence of the reducing compound such as ascorbic acid, various techniques using a metal ion as an oxidizing agent have been developed.
(1) J. Am. Chem. Soc., 89, 4176 (1967); 89, 7104 (1967); and 90, :3:386 (1968) describe dynamic study of oxidation of ascorbic acid according to pH values in the presence of iron and copper chelates, and revealed that the metal ion oxidized ascorbic acid. However, these papers do not relate to the study of behavior of ascorbic acid in an assay system.
(2) Japanese Patent Publication No. :39871/1988 (corresponding to U.S. Pat. No. 4,288,541 and EP-A-0 027 2:36) discloses the addition of mercury (II) sarcosinate to a composition for analysis to avoid the adverse influence of a salt of ascorbic acid. However, when such metal complex is added to a composition for analysis containing an organic hydroperoxide and an indicator, the indicator reacts with the metal complex to provide a false-positive result. In addition, the mercury complex is not preferable because of toxicity of mercury.
(3) Japanese Patent Publication No. 67139/1988 (corresponding to EP-A-0 043 469) discloses a Co (III) complex as a compound which removes an interfering function of ascorbic acid. However, when the Co (III) complex is added to the composition for analysis containing the organic hydroperoxide and the indicator, the indicator reacts with the metal complex to provide a false-positive result.
(4) Japanese Patent Kokai Publication No. 286099/1990 (corresponding to U.S. Pat. No. 5,079,140 and EP-A-O 392 305) discloses a system containing a first oxidizing agent comprising a water-soluble polymer which generates a copper (II) complex and a second oxidizing agent selected from the group consisting of inorganic oxidizing compounds, organic peroxides and organic N-haloderivative. However, the oxidizing rate of the copper (II) complex is low, and this system is not effective.
(5) Japanese Patent Publication No. 4123/1989 discloses the addition of a divalent or trivalent iron complex of a compound of the formula: R.sub.1 R.sub.2 NCH.sub.2 COOH or R.sub.3 R.sub.4 NXNR.sub.5 CH.sub.2 COOH or a divalent or trivalent iron complex of gluconic acid to remove ascorbic acid in the measurement of components in body fluids.
(6) Japanese Patent Publication No. 18630/1992 (corresponding to U.S. Pat. No. 4,587,220 and EP-A-0 123 115) discloses the addition of a trivalent iron chelate of a polycarboxyalkylamine derivative to a composition for detecting the peroxide active material.
(7) In addition, Canada Patent No. 844,564 discloses a testing piece comprising a porous part impregnated with a glucose-responsive reagent, and an additional part which receives a urine sample and contains an ion-exchange material that can absorb ascorbic acid in the urine. The testing piece carrying the iron-exchange material has a complicated structure and requires a longer time for analysis than a conventional assay methods.
(8) Japanese Patent No. 39198/1981 and U.S. Pat. No. 4,168,205 eliminate the influence of ascorbic acid by the addition of ascorbic acid oxidase to a formulation in a test reagent paper. While this method is effective, it is uneconomical since a large amount of ascorbic acid oxidase is necessary to eliminate the interference of ascorbic acid. In addition, ascorbic acid oxidase reacts with ascorbic acid but does not with other reducing materials, and is a very unstable enzyme.
(9) Japanese Patent Publication No. 4861/1990 (corresponding to U.S. Pat. No. 4,743,559 and EP-A-0 037 056) discloses the addition of an iodate (pH of 5 to 9) in an amount of 0.5 to 2 g/dl to a test reagent to eliminate the influence of the reducing material such as ascorbic acid.
(10) Japanese Patent Publication No. 15280/1989 discloses the treatment of a sample with iodic acid or iodate to eliminate the influence of the reducing material. However, iodine which is liberated by the reaction of the reducing agent with the iodic acid or iodate oxidizes various indicators to provide false-positive result. Further, the iodate oxidizes the indicator to color the background.